Insulation stripping connectors (sometimes referred to in the art as “insulation displacement connectors,” “IDC's” or “terminals”) are widely used in industry, particularly within the telecommunication, automotive solenoid and electrical motor fields. Insulation stripping connectors offer reliable, gas-tight connections, and their ease and speed of installation eliminate the need for wire stripping, crimping, or soldering techniques. However, the problem with existing insulation stripping connectors is that they accommodate only a small range of wire sizes. For instance, many existing connectors feature rigid beams or legs that engage wire when such connectors are inserted into their associated housings or bobbins. Since the beams or legs offer very little, if any, flexibility, the connectors can only accommodate two to three wire sizes. Consequently, a user must purchase, stock, and utilize many different insulation stripping connectors for use with a wide range of wire sizes.
U.S. Pat. No. 4,749,365 to Magnifico (the “Magnifico '365 Patent”) attempted to address the aforementioned shortcoming of prior insulation stripping connectors. The Magnifico '365 Patent discloses an insulation displacement terminal that includes flexible inner beams and stiff outer beams that allow for the accommodation of a range of wire sizes. However, the range of wire sizes that can be used in conjunction with the terminal disclosed in the Magnifico '365 Patent is limited by the elastic limit of the material used to manufacture the terminal, particularly the elastic limit of the terminal's inner beams. For instance, a large size wire that engages the terminal may force apart the inner beams to a point that exceeds their elastic limit, resulting in the inner beams losing their elasticity. While exceeding the elastic limit of the inner beams may make an acceptable initial connection with the wire, the failure of this connection can occur due to various environmental conditions, such as ordinary vibrations exerted upon the terminal, as well as diameter changes of the wire, which are caused by reduced or elevated temperatures. Since the inner beams have lost their elasticity, a gas-tight connection between the terminal and the wire is lost. As a result, molecules of oxygen or other gases can enter the interface between the terminal and the wire, thereby causing a buildup of corrosion on the terminal and/or the wire. Consequently, the loss of the gas-tight connection between the terminal and the wire causes intermittent or open circuits during use. Thus, the range of wires that can be reliably used with the terminal disclosed in the Magnifico '365 Patent is severely limited.
In addition, the terminal covered by the Magnifico '365 Patent discloses small slits and coined areas located at common expanses (where the inner and outer beams are joined). The slits and the coined areas partially divide the inner and outer beams. The Magnifico '365 Patent discloses that the function of the slits and the coined areas is to create a force that pushes the inner beams toward each other when the terminal engages a wire. The Magnifico '365 Patent further discloses that this configuration allows for the manufacture of a narrow wire slot, thereby increasing the range of wire sizes that can be used in conjunction with the terminal, as well as improving the connecting features of the terminal. However, the problem with this configuration is that the sizes of the slits and the coined areas are very difficult to manufacture within the terminal's specifications, due to variations in the hardness of the material used to manufacture the terminal, as well as the sharpness of the tools used to create the slits and the coined areas. Since the size of the wire slot depends upon the sizes of the slits and the coined areas, any deviation in the sizes of slits and/or the coined areas would affect the size of the wire slot. For instance, if a slit and/or a coined area is manufactured too small, then the width of the wire slot will be too large. As a result, the inner beams would not maintain a sufficient connection with the wire. On the other hand, if a slit and/or a coined area are manufactured too large, then the width of the wire slot will either be too narrow or the wire slot will be closed up (i.e., the inner beams would be preloaded and, therefore, converge with one another). As a result, a wire that is inserted in the wire slot may be severed when it is engaged with the terminal. Moreover, if the slit contains a gap, then the elastic characteristics of the inner beams would be eliminated. Also, if the slit is manufactured too long, then the inner beams will almost be severed from the outer beams, thereby eliminating the elastic characteristics of the inner beams. As a result of any of the foregoing scenarios, the terminal would not provide a reliable electrical or gas-tight connection with the wire.
Accordingly, there is a need for an insulation stripping connector that can accommodate a large range of wire sizes, while providing a reliable gas-tight connection between the connector and the wire and, at the same time, maintaining the elastic integrity of the inner legs of the connector.